In our earlier U.S. Pat. No. 4,682,922 we disclose a wheel support system comprised of a pair of normally horizontal arms that in use are both perpendicular to a horizontal support beam and horizontally parallel to each other. A wheel of a vehicle whose other wheels are similarly supported is embraced between this pair of arms below its horizontal centerpoint with the wheel surface in tangential engagement with the respective two arms. The arms are movable as pairs along the beam and can be fixed at any one of a multiplicity of longitudinally defined positions therealong so as to accommodate vehicles of different wheelbases. Such pairs of arms are normally used in a vehicle-transporting truck or railroad car onto which a group of vehicles of differing wheelbases are carried. The beams of such a transporter extend sufficiently horizontally so as to prevent the vehicles from falling out of the seats formed by means of the pairs of arms, and in fact the beams are often disposed in an inclined mode as defined by means of a small acute angle with respect to the horizontal.
In the above-cited patent the arms of each pair are pivotally mounted upon a frame having as inverted J-section that itself slides along the support beam. The arms can be pivoted into a horizontal position parallel to the beam so they can be swung out of the way as another vehicle moves past them during loading or unloading or as the device is slid into position. The longitudinal spacing between adjacent arms is therefore fixed by the effective length of the frame, although it is possible to vary this frame length within certain limits. The top beam surface can be provided with indexing formations, for instance a rack-like row of teeth, within which the frame is engaged so as to prevent the frame from sliding longitudinally once the same is hooked in place.
Each arm of this device is carried upon the lower end of an upright shaft journaled within the frame and provided at its upper end with a hook plate that engages over the top surface of the beam and behind the rear surface thereof, that is, the surface opposite the front surface that is disposed toward the vehicle being supported. Thus not only does the downward force exerted by means of the vehicle upon the holder ensure that it will be hooked in place, but the force trying to rotate the shafts outwardly away from each other will pivot these hook plates and cause then to engage the beam solidly because the inner vertical edge of the outer pendant leg of each hook plate engaging the rail will also secure it longitudinally in place.
Such an arrangement, while being a substantial advance over other similar devices, nevertheless requires additional improvement. Movement of the large assembly comprised of two arms and the frame is fairly difficult for one person to achieve, especially once it has been wedged in place. Furthermore adjusting the arm spacing is difficult and must be undertaken for each individual unit. When not in use these devices also rattle and thereby create an annoyance for the driver. Making the various mechanical adjustments needed for each different vehicle and/or wheel size is also a considerably onerous task.